

The X1 line is more integrated and they aren’t the line to buy if someone wants to upgrade their laptop. The RAM is soldered on the board to get it as thin as possible, for example.
I have a gen 9 X1, and it runs Linux great! It’s also not getting upgraded aside from the SSD.

Asus NUC with Intel N150 is what I’ve been looking at. Up-board.org has a credit card sized dev board with the proc, if form factor is a requirement.
There is also the N350 with 8 cores for more power.